Standard ROM sets (like full MAME sets) often mix thousands of horizontal and vertical titles, making it difficult to navigate a menu on a vertically-mounted screen. A vertical-only pack offers several advantages:
Vertical orientation was the standard for many "Golden Age" classics and remains popular for specific genres. Why did early arcade games use vertical displays? vertical arcade rom pack
A is a curated collection of classic games originally designed for "portrait" or vertically-oriented monitors. These packs are essential for enthusiasts building dedicated vertical cabinets or using rotating monitors, as they eliminate "letterboxing" and ensure the game fills the entire screen as intended. Why You Need a Dedicated Vertical Pack Standard ROM sets (like full MAME sets) often